Delta Herculis (δ Herculis, abbreviated Delta Her, δ Her) is a multiple star system in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the Gr ...

. Its light produces to us

apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

3.12, as such the third-brightest star in the large, fairly dim constellation. Based on

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

measurement taken during the

Hipparcos ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions and distances of ...

mission, it is approximately from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

Components

It consists of a binary pair, designated Delta Herculis A, together with three potential companions, suffixed B, C and D. Furthermore B is believed to be an optical binary. A's components are designated Delta Herculis Aa (officially named Sarin , the traditional name of the system) and Ab. The angular separation between the main component A and the component B, which has a magnitude of 8.74, is 8.5 arcsecond

Nomenclature

''δ Herculis'' ( Latinisation of names, Latinised to ''Delta Herculis'') is the system's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

. The designations of the four constituents as ''Delta Herculis A'', ''B'', ''C'' and ''D'', and those of ''A's'' components - ''Delta Herculis Aa'' and ''Ab'' - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

(IAU). It bore the traditional name ''Sarin''. In 2016, the

organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name ''Sarin'' for the component Delta Herculis Aa on 12 September 2016 and it is now so included in the List of IAU-approved Star Names. In the catalogue of stars in the ''Calendarium'' of Al Achsasi al Mouakket, this star was designated ''Menkib al Jathi al Aisr'', which was translated into

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

as ''Humerus Sinister Ingeniculi'', meaning ''kneeler's left shoulder''. In Chinese, (), meaning '' Left Wall of Heavenly Market Enclosure'', refers to an asterism which represents eleven old states in China which is marking the left borderline of the enclosure, consisting of Delta Herculis, Lambda Herculis,

Mu Herculis Mu Herculis (μ Herculis) is a nearby quadruple star system about 27.1 light years from Earth in the constellation Hercules (constellation), Hercules. Its main star, Mu Herculis A is fairly similar to the Sun although more hig ...

, Omicron Herculis, 112 Herculis, Zeta Aquilae, Theta¹ Serpentis, Eta Serpentis, Nu Ophiuchi, Xi Serpentis and Eta Ophiuchi. Consequently, the

Chinese name Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethni ...

for Delta Herculis itself is (, ), and represents the state of Wei (魏), together with 33 Capricorni, according to Ian Ridpath version or Phi Capricorni and Chi Capricorni in R.H. Allen's versionStar Names - R.H.Allen p.142
/ref> in '' Twelve States'' (asterism).

Properties

Delta Herculis A presents as an A-type

main-sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color versus brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or dwarf stars, and positions of star ...

subgiant A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution ...

with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

of A3IV. It has both a mass and radius that are roughly two times solar yielding a total

luminosity Luminosity is an absolute measure of radiated electromagnetic radiation, electromagnetic energy per unit time, and is synonymous with the radiant power emitted by a light-emitting object. In astronomy, luminosity is the total amount of electroma ...

of about

References

External links

*Jim Kaler's Stars, University of Illinois
DELTA HER (Delta Herculis)
*An Atlas of the Universe

{{DEFAULTSORT:Delta Herculis Hercules (constellation) Herculis, Delta Sarin Herculis, 065 A-type subgiants 084379 6410 156164 Durchmusterung objects

Components

Nomenclature

Properties

See also

References

External links